Lighting devices are used in various applications. The lighting device may be, for example, used as a BLU (backlight unit) of a display such as an LCD (liquid crystal display), a TV, a computer, a mobile phone, a smart phone, a personal digital assistant (PDA), a gaming device, an electronic reading device or a digital camera. Besides, the lighting device may be used for indoor or outdoor lighting, stage lighting, decorative lighting, accent lighting or museum lighting, and the like, as well as special wavelength lighting required for horticulture and biology.
A typical lighting device is, for example, one used as a BLU of a LCD, and the like, and there is a device which emits a white light by combining phosphors such as a blue LED (Light Emitting Diode) and a YAG (Yttrium aluminum garnet).
In addition, recently, researches related to a lighting device emitting a white light by using wavelength conversion particles, for example, quantum dots, in which the color of light to be emitted varies depending on the size of particles, have been steadily progressing.
In particular, studies for solving problems to reduce the efficiency due to exposure to gases such as oxygen and increasing wavelength conversion efficiency of quantum dots themselves, and the like have been actively carried out.
(Patent Document 1) Korean Laid-Open Patent Publication No. 2011-0048397
(Patent Document 2) Korean Patent Publication No. 2011-0038191